Wolters Kluwer Health may email you for journal alerts and information, but is committed
to maintaining your privacy and will not share your personal information without
your express consent. For more information, please refer to our Privacy Policy.

Author Information

There have been many case reports describing onset of myasthenia gravis (MG) after cardiac surgery (1-3) and after administration of neuromuscular blocking agents in preparation for surgery (4). We describe a patient in whom severe generalized MG developed immediately after cataract surgery, requiring thymectomy and long-term immunosuppressive therapy.

A 52-year-old right-handed white man developed progressive weakness 1 day after outpatient cataract surgery on the right eye. His past medical history was significant for insulin-dependent diabetes treated with an insulin infusion pump. He had diabetic peripheral neuropathy.

Before surgery, he reported no other neurologic symptoms. The cataract surgery was uncomplicated, and routine topical analgesics had been applied on the eye before the procedure. The patient noticed nothing unusual until he removed the eye patch the day after surgery and experienced diplopia followed by bilateral ptosis. Over the next 2 weeks, he noted progressive fatigue and limb weakness. A Tensilon test performed 3 weeks after surgery showed subjective and objective strength improvement, and pyridostigmine and prednisone were started. One week later, he developed neck weakness and difficulty swallowing and was hospitalized.

On admission, he had 4 mm of ptosis bilaterally. The right eye had no movement in any direction. The left eye had 80% adduction and abduction and full vertical ductions. He was hoarse and had difficulty swallowing liquids. He had 4/5 weakness in distal and proximal muscles. His reflexes were 1+ throughout. Plantar reflexes were flexor. Sensory signs included bilateral decreased temperature, vibration, and joint position sense distal to the knees.

Slow repetitive nerve stimulation (3 Hz) of the bilateral median nerve at rest and 1 minute after exercise showed compound muscle action potential (CMAP) amplitude decrements of 35% and 20%, respectively, consistent with a diagnosis of neuromuscular junction disorder. The baseline CMAP amplitude was normal without an incremental response of CMAP amplitude after 10 seconds of maximum isometric contraction, making it less likely to be a presynaptic condition. Sensory nerve action potentials were absent, indicating a polyneuropathy. Surprisingly, the patient had moderate to severely prolonged CMAP onset latencies with decreased conduction velocity in all extremities and preserved CMAP amplitudes, indicating a demyelinating polyneuropathy, which is unlike the findings seen in typical diabetic neuropathy.

The patient was treated with a course of plasmapheresis and his bulbar symptoms improved. Three months after his initial symptoms, he underwent thymectomy, with the specimen showing normal thymic tissue. With 60 mg prednisone, 80 mg pyridostigmine 3 times/day, and 250 mg mycophenolate mofetil 2 times/day, he continues to have binocular oblique diplopia that is worse in up-and-left gaze and is ambulatory with minimal assistance.

It is rare to identify a trigger for the onset of MG. With respect to cardiothoracic surgery (1-3), it has been presumed that manipulation of thymic remnants provided a trigger for autoimmune damage. It is possible that damage induced during the surgical procedure could induce a new wave of autoantibody production that is not readily subject to immune regulation in susceptible individuals.

A well-documented effect of neuromuscular blockade agents such as vecuronium, which are administered during tracheal intubation, is to unmask undiagnosed MG. The diagnosis is made when patients fail to maintain adequate spontaneous ventilation after the procedure (4,5). Subsequently, it is discovered that such patients have a history of ptosis, diplopia, dysphagia, dysarthria, fatigue, and weakness.

We postulate that the cataract surgery itself or local anesthetics triggered an autoimmune response or aggravated a preexisting subclinical MG in this patient.

Enter and submit the email address you registered with. An email with instructions to reset your password will be sent to that address.

Email:

Password Sent

Link to reset your password has been sent to specified email address.

Remember me

What does "Remember me" mean?
By checking this box, you'll stay logged in until you logout. You'll get easier access to your articles, collections,
media, and all your other content, even if you close your browser or shut down your
computer.

To protect your most sensitive data and activities (like changing your password),
we'll ask you to re-enter your password when you access these services.

What if I'm on a computer that I share with others?
If you're using a public computer or you share this computer with others, we recommend
that you uncheck the "Remember me" box.